Most of the examples given in the previous section of this tutorial used a Wedge-Dash notation. Additionally, molecules were oriented such that at least one relationship between molecules - such as superimposibility - could be determined.

However, molecules are not normally presented in such a straight-forward way. A variety of notations can be used and compared, and molecules can be oriented in space such that their relationship is not obvious.

There are two main categories of molecules, those that are in a straight-chain, or acyclic, form, and those that are in a ring, or cyclic, orientation.

The following pages will give information on the different structural notations, so that more complex molecules can be compared in later sections.